When McDonald’s promised “no purchase necessary” for its famous Monopoly sweepstakes, one man took the fast-food chain very seriously.

Brandon Duncombe, a 28-year-old writer from West Palm Beach, Fla., read the rules of McDonald’s Monopoly carefully and discovered a “no purchase necessary” claim in the fine print, Bargaineering reports.

According to lawyer Alan L. Friel, contests and sweepstakes must include a "no consideration" clause such as "no purchase necessary." Otherwise, the contest is considered an illegal lottery.

That means customers can request game pieces be sent to them in the mail without buying anything. The catch? Each letter must be handwritten and sent along with a self-addressed, stamped envelope. So, even though you technically can play the game for free, it's going to take a toll both on your time and your wallet.

"We always talk about how the cheapest way to play is to mail in letters," Duncombe told The Huffington Post in an interview. "So why don’t we send 100 letters and see what we get back?"

Despite the cost of postage and the human cost of writing the letters, Duncombe did the math and figured out that it was cheaper for him to play the game this way rather than going to McDonald’s and buying a meal. So, he wrote 100 letters by hand -- costing about 90 cents each in postage, plus the cost of the envelope -- to receive 400 game stamps (four stamps per letter) from McDonald’s. In total, he said it took him about 10 hours and cost about $117.

According to Duncombe's calculations, the cheapest menu item at McDonald’s that comes with game pieces is an order of hash browns. At 99 cents, that's more than the cost of a letter. Although the investment promises no return and the savings aren’t that great -- $198 for 200 orders of hash browns versus $117 to mail the letters -- Duncombe said he is more interested in what McDonald’s reaction will be than actually making a profit.

“After a quick Internet search, I wasn’t able to come across anyone who’d attempted to send in this many letters, so I’m curious to see if McDonald’s will live up to their word and mail me 400 game stamps,” he wrote on Bargaineering.

Duncombe stuffed all 100 letters into a mailbox about two weeks ago and received 98 of his 100 letters back from McDonald's with his requested pieces included. He wrote in an email that he doesn't plan on winning much, but rather played the game this way for fun. For a step-by-step guide to Duncombe’s McDonald’s Monopoly scheme, click here.

To play the McDonald's Monopoly game, participants collect pieces of the Monopoly board that are included with certain menu items. Certain combinations of pieces, like Vermont Avenue and Connecticut Avenue, earn prices like $5,000 in cash, while other pieces give away a free burger or a side of fries.

So what are the odds of winning the sweepstakes? To win $50 by getting Mediterranean and Baltic Avenue, your chances are 1 in 402,602, according to About.com. For one of the larger prizes -- $1,000,000 -- your chances are about 1 in 3 billion.

Despite the odds stacked against him, 30-year-old Wisconsin resident Jon Kehoe won the million-dollar prize during last year’s contest, according to the Journal Sentinel. Kehoe said he bought a McRib meal with the last of his unemployment check. When he peeled back the label on his drink, there was a Park Place and a Boardwalk -- the exact pieces needed for the grand prize.

Personal finance blog Wisebread suggests that one of the best ways to increase your odds in the game is to look on eBay or Craigslist for the pieces you have or want. Chances are you will see dozens of people willing to make a trade.